Secant Newton

This command is used to construct a SecantNewton algorithm object which uses the two-term update to accelerate the convergence of the modified newton method. The command is of the following form:

algorithm SecantNewton < -iterate $tangIter >
        < -increment $tangIncr > < -maxDim $maxDim >

tangIter	tangent to iterate on, options are current, initial, noTangent. default is current.
tangIncr	tangent to increment on, options are current, initial, noTangent. default is current
maxDim	max number of iterations until the tangent is reformed and acceleration restarts (default = 3)

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Notes

The default “cut-out” values recommended by Crisfield (\(R_1=3.5\), \(R_2=0.3\)) are used.

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References

Crisfield, M.A. “Non-linear Finite Element Analysis of Solids and Structures”, Vol. 1, Wiley, 1991.

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Code Developed by: Michael Scott, Oregon State University